From 9a23df7d623477255d08e9a5fe69399eb0bd0a76 Mon Sep 17 00:00:00 2001 From: Baptiste Jonglez Date: Sat, 12 Jul 2014 14:50:27 +0900 Subject: [PATCH] Document environment variables, especially MTR_OPTIONS --- mtr.8 | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/mtr.8 b/mtr.8 index f664b1d..16770c5 100644 --- a/mtr.8 +++ b/mtr.8 @@ -315,6 +315,37 @@ of file descriptors. .TP .B \-M \fIMARK\fR, \fB\-\-mark \fIMARK MISSING +.SH ENVIRONMENT +.B mtr +recognizes a few environment variables. +.TP +.B MTR_OPTIONS +This environment variable allows to specify options, as if they were +passed on the command line. It is parsed before reading the actual +command line options, so that options specified in +.B MTR_OPTIONS +are overriden by command-line options. + +Example: + +.BI MTR_OPTIONS ="-4\ -c\ 1" +.B mtr +.I \-6\ localhost + +would send one probe (because of +.I -c\ 1\c +) towards +.B ::1 +(because of +.IR -6 , +which overrides the +.I -4 +passed in +.B MTR_OPTIONS\c +). +.TP +.B DISPLAY +Used for the GTK+ frontend. .SH BUGS Some modern routers give a lower priority to ICMP ECHO packets than to other network traffic. Consequently, the reliability of these -- 2.47.2